Magnetically operating switch

ABSTRACT

A moisture and tamper proof lid switch on a clothes washer top is magnetically operated by a magnet carried on the swinging edge of the washer access lid. The switch has one pair of stationary contacts. A second pair of movable contacts is loosely supported by a spring on a ferromagnetic plunger and adapted to close on the stationary contacts and compress the spring when the lid is closed and the magnet is next to the plunger. As the lid is opened, the compressed spring induces movement in the plunger which impacts on the movable contacts to open the lid switch suddenly and surely.

Moorman MAGNETICALLY OPERATING SWITCH Dec. 3, 1974 Primary ExaminerG. Harris [76] Inventor: Earl Moorman, 231 Ashwood Attorney, Agent, or Firm-Frederick M. Ritchie Ave., Dayton, Ohio 45405 T C 57 ABS RA T [22] Filed: Feb. 19, 1974 1 Y A moisture and tamper proof lid switch on a clothes PP 443,803 washer top is magnetically operated by a magnet carried on the swinging edge of the washer access lid. 52 us. Cl. 335/205, 335/207 The switch has one Pair of Stationary Contacts- A 51 Int. Cl. HOlh 9/00 0nd of movable Contacts is loosely Supported by a 58 Field of Search 335/205, 206, 207 Spring a ferromagnetic Plunger and adapted close on the stationary contacts and compress the [56] References Cited spring when the lid is closed and the magnet is next to UNITED STATES PATENTS the plunger. As the lid is opened, the compressed spring induces movement in the plunger which imgliggljg g y et pacts on the movable contacts to open the lid switchgno 3,7l7,830 2/1973 Athey 335/207 Suddenly and surely 5 Claims, 4 Drawing Figures PAIENIEL 11H: 31914 lI/II'VIIA MAGNETICALLY OPERATING SWITCH This invention relates to a magnetically operated switch utilizing a spring induced inertia impact to open the switch. More particularly, the invention relates to such a switch for use as a spin interlock in conjunction with a clothes washer access lid.

Prior art clothes washers have included an interlock switch to deenergize the motor or disconnect the driving mechanism which rotatably drives a spin tub. This happens whenever the user opens the washer access lid while the tub is spinning. Generally, the switch is designed to deenergize the motor when the access lid opens a predetermined gap at its swinging edge. In the past, some interlock switches have been located near the lid hinge. But this requires difficult close tolerance adjustments of the switch at the hinge side of the lid to cause the switch to deenergize the motor at least by the time the remote swinging side of the lid is gapp ed open two inches. Then, too, the switch plunger in such arrangements is accessible and can be pushed by the user to spin the tub with the washer lid open. Moreover, the plunger opening serves also as a passageway whereby moisture may reach the switch. This invention is directed to an easily adjustableinterlock switch which, in a clothes washer adaptation is moisture proof and tamper proof.

Accordingly, it is a general object of this invention to provide a lid interlock switch for a clothes washer which is moisture proof and tamper proof.

Another object is the provision of an electrical power supply switch construction which assures contact opening by impacting a plunger on a contact arm to break any tack welding of the contacts.

A still further object is the provision of a magnetically operated switch utilizing a spring induced inertia impact to open the switch contacts and break any tack welding thereof.

A more specific object of this invention is the provision in a clothes washer of a magnetically operated lid interlock switch for the access opening of the washer wherein the access lid carries a permanent magnet and the switch is carried on the washer in a housing which is inaccessible to the user and impervious to moisture in the vicinity of the access opening, and wherein the switchhas a ferromagnetic plunger which is spring induced to impact on the switch contacts for opening thereof simultaneously with opening of said access lid.

FIG. 1 showing the condition of the interlock switch with the access lid of the clothes washer in its closed position;

FIG. 3 is a sectional view of the interlock switch taken along line 4-4 in FIG. 1 at the instant of inertia impact to open the switch as the access lid starts to move toward its open position; and

FIG. 4 is a sectional view of the interlock switch taken along line 44 in FIG. 1 showing the condition of the interlock switch after the access lid has moved to its open position. i

This invention in accordance with FIG. 1 relates to a waterproof, tamper proof switch 10 adapted to be operated by a moving magnet 12. The switch is illustrated on a clothes washer Has an interlockswitch adapted to interrupt an electrical power supply to the washer whenever an access lid 16 is opened to expose an access opening 18.

In general the switch is comprised of one pair of stationary contacts 20, 22 and a second pair of movable contacts 24, 26 adapted to close on the stationary contact pair in response to movement of the magnet 12. The movable contact pair is loosely carried at 30 on the shaft 32 of a movable support plunger 34 of magnetic material. A spring 36 between the shaft and the movable contact pair normally urges the movable contact pair against a shoulder 38 of the support plunger. When the moving magnet 12 is in juxtaposition with plunger 34, the plunger is attracted and the contact pairs close with spring 36 serving to increase contact force between the contact pairs (FIG. 2). When magnet 12 is moved away, spring 36 accelerates the gravitational drop of the plunger and the spring induced impact of the plunger shoulder on the movable contact pair (FIG. 3) facilitates opening the switch (FIG. 4) by overcoming any tack welding of the contacts. I 1

More particularly, switch 10 is comprised of a nylon switch case 50 having an upper cavity 52, a lower cavity 54 and a bore 56 interconnecting the two cavities. A nylon upper switch cap 58 closes the upper cavity 52 and a lower nylon switch cap 60 closes the lower cavity 54. The upper switch cap overlies the top of washer 14 in the vicinity of the access opening 18 and is fastened to the switch case by screws 62. A similar fastening arrangement (not shown) connects the lower switch cap 60 to the switch case. Spring clips 66, 68 snap-fasten the switch 10 to the top of the washer through an opening 70 therein.

Stationary contacts 20, 22 extend outside the switch case and are adapted thereby with connector spades for electrically connecting the interlock switch 10 into the power supply of the clothes washer. Movable contacts 24, 26 form part of an electrically conductive movable contact arm 72 having an opening 74 larger than shaft 32 to accommodate aloose interfit of the arm on the shaft.

Support plunger 34 includes an actuating plate portion 78 of magnetic material in upper cavity 52 and an impact portion 80 in bore 56 connected at its. upper endto actuating plate 78 and forming at its lower end the shoulder 38. The plunger also includes shaft 32 depending from the impact portion with spring 36 thereon. The spring supports movable contact arm 72 at its upper end and is retained at its lower end on shaft 32 by washer 84 and retainer spring clip 86 snapfastened in an annular groove of the shaft. A suitable plunger may be formed from low carbon steel provided with a 0.0002 inch nickel plate finish. The actuating plate 78 is 1.0 inch by 0.620 inch by 0.090 inch thick.

Impact portion 80 is 0.380 inch long and 0.280 inch in diameter. Shaft portion 32 is 0.100 inch in diameter and 0.500 inch long overall with a distance between shoulder 38 and the retaining clip groove of 0.340 inch.

Spring 36 is adapted to yieldingly urge the movable contact arm 72 against shoulder 38 when the washer access lid is open (FIG. 4) and to increase contact pressure between stationary contacts 20, 22 and-movable contacts 24, 26, respectively, when the washer access lid is closed (FIG. 2). Spring 36 will also initiate the downward gravitational movement of plunger 34 when the access lid starts to open, thereby to increase the impact of shoulder 38 on movable contact arm 72 (FIG. 3). One suitable spring for this purpose is formed of stainless steel 0.012 inch diameter wire into a coil having a free length 0.320 inch and an inside diameter of 0.140 inch, the spring rate being 1.3 pounds per inch in 5.9 active turns.

Magnet 12 is a permanent magnet retained on the access lid 16 in a nylon housing 90 and must attract the top surface of actuating plate 78 with a force of 40 grams minimum at a distance of 0.180 inch.

Certain elements cooperate in the foregoingswitch to provide a suitable impact which assures a sudden, sure opening of the interlock switch irrespective of any tack welding; A desired impact depends on the spring 36, the weight of plunger 34 and the distance A traveled by the plunger before it impacts on movable contact arm 72. These may be varied in accordance with the teachings of this invention to obtain the force necessary to move contacts 24, 26 away from stationary contacts 20,22.

While the embodiment of the present invention as herein disclosed constitutesa preferred form, it is to be understood that .other forms might be adopted.

What is claimed is:

1. ln adomestic clothes washer, the combination of a clothes washer wall having an access opening, an access lid hingedly mounted with respect to said wall along one edge of said lid and adapted to close said access opening when a movable edge of said lid lies adjacent said wall, a magnet located on said movable edge, and a magnetically operated switch located adjacent said magnet when said'access lid is closed, said switch comprising a switch housing of nonmagnetic material in fixedrelation to said wall and generally imperforate to moisture and access through said wall in the vicinity of said access opening, a pair of stationary contacts in said housing adapted to be electrically connected in the power supply circuitof said clothes washer, a pair of movable contacts in said housing for electrically bridging said stationarycontacts to close said power supply circuit,'and support means for said pair of movable contacts axially movable in said housing in two directions, said support means including as a unit an actuating plate portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said pair of movable contacts between said spring and said impact portion, said actuating plate portion being of magnetic material axially movable in response to the presence of said magnet when said access lid is closed for axially moving said support means in one direction to move said movable contacts into bridging relation with said stationary contacts, said support means axially movable in the opposite direction in response to the absence of said magnet when said access lid is open to move said movable contacts out of bridging relation with said stationary contacts, said shaft portion loosely interfittingwith said pair of movable contacts and axially movable relative thereto, said impact portion havinga shoulder spaced a predetermined distance from said pair of movablecontacts when said access lid is closed to condition the shoulder of said impact portion for impacting on said pair of movable contacts when said access lid is opened, said spring supporting said pair of movable contacts against said shoulder when said access lid is open, said spring maintaining the bridging relation of said pair of movable contacts with said stationary contacts after the axial movement of said support means in said one direction when said access lid is closed and inducing the axial movement of said support means in the opposite direction to cause said shoulder to impacton said pair of movable contacts when the access lid is opened, the mass of said support means in cooperation with saidpredetermined distance and the rate of said spring being sufficient to suddenly and surely break the bridging relation and any tack welding of said movable contacts with said stationary contacts, thereby to open the power supply circuit as soon as said access lid is opened.

2. The combination of claim 1 wherein said clothes washer wall is'horizontal and the axial movement of said support means in said opposite direction is aided by gravity.

,3. A magnetically operated switch adapted to be located adjacent a magnet means which is selectively present or absent from the'location of the switch, said switch comprising a switch housingof nonmagnetic material generally imperforate to moisture and access from one side thereof, a pair of stationary contacts in said housing adapted to be electrically connected in an electrical power supply circuit, a pair of movable contacts in said housing for electrically bridging said stationary contacts to close saidpower supply circuit, and support means for said pair of movable contacts axially movable in said housing in two directions, said support means including as a unit an actuating plate portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said pair of movable contacts between said spring'and said impact por} tion, said actuating plate portion being of magnetic material axially movable in response to the presence of said magnet means for axially moving said support means in one direction to move said movable contacts into bridging relation with said stationary contacts, said support means axially movable in the opposite direction in response to the absence of said magnet means to move said movable contacts-out of bridging relation with said stationary contacts, said shaft portion loosely interfitting with said pair of movable contacts and axially movable relative thereto, said impact portion having a shoulder spaced a predetermined distance from said pair of movable contacts when said magnet means is present, said spring supporting said pair of movable.

contacts against said shoulder when said magnet means is absent, said spring maintaining the bridging relation of said pair of movable contacts with said stationary contacts after the axial movement of said support means in said one direction when said magnet means is present and inducing the axial movement of said sup port means in the opposite direction to cause said shoulder to impact on said pair of movable contacts at the moment said magnet means is absent, the mass of said support means in cooperation with said predetermined distance and the rate of said spring being sufficient to suddenly and surely break the bridging relation and any tack welding of said movable contacts with said stationary contacts, thereby to open the power supply circuit as soon as said magnet means is absent.

4. The magnetically operated switch of claim 3 wherein said magnet means is a permanent magnet.

5. A magnetically operated switch adapted to be located adjacent a magnet means which is selectively present or absent from the location of the switch, said switch comprising stationary contact means adapted to be electrically connected in an electrical power supply circuit, movable contact means for electrically connecting said stationary contact means to close said power supply circuit, and support means for said movable contact means movable in two directions, said support means including as a unit an actuating portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said movable contact means between said spring and said impact portion, said actuating portion being of magnetic material movable in response to the presence of said magnet means 4 for moving said support means in one direction to move said movable contact means into connecting relation with said stationary contact means, said support means movable in the opposite direction in response to the absence of said magnet means to move said movable contact means out of connecting relation with said stationary contact means, said shaft portion freely movable relative to said movable contact means, said impact portion having a shoulder spaced a predetermined distance from said movable contact means when said magnet means is present and said movable contact means is in connecting relation with said stationary contact means, said spring supporting said movable contact means against said shoulder when said magnet means is absent, said spring maintaining the connecting relation of said movable contact means with said stationary contact means after the movement of said support means in said one direction when said magnet means is present and inducing the movement of said support means in the opposite direction to cause said shoulder to impact on said movable contact means at the moment said magnet means is absent, themass of said support means in cooperation with said predetermined distance and the rate of said spring being sufficient to suddenly and surely break the connecting relation and any tack welding of said movable contact means with said stationary contact means, thereby to open the power supply circuit as soon as said magnet means is absent. 

1. In a domestic clothes washer, the combination of a clothes washer wall having an access opening, an access lid hingedly mounted with respect to said wall along one edge of said lid and adapted to close said access opening when a movable edge of said lid lies adjacent said wall, a magnet located on said movable edge, and a magnetically operated switch located adjacent said magnet when said access lid is closed, said switch comprising a switch housing of nonmagnetic material in fixed relation to said wall and generally imperforate to moisture and access through said wall in the vicinity of said access opening, a pair of stationary contacts in said housing adapted to be electrically connected in the power supply circuit of said clothes washer, a pair of movable contacts in said housing for electrically bridging said stationary contacts to close said power supply circuit, and support means for said pair of movable contacts axially movable in said housing in two directions, said support means including as a unit an actuating plate portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said pair of movable contacts between said spring and said impact portion, said actuating plate portion being of magnetic material axially movable in response to the presence of said magnet when said access lid is closed for axially moving said support means in one direction to move said movable contacts into bridging relation with said stationary contacts, said support means axially movable in the opposite direction in response to the absence of said magnet when said access lid is open to move said movable contacts out of bridging relation with said stationary contacts, said shaft portion loosely interfitting with said pair of movable contacts and axially movable relative thereto, said impact portion having a shoulder spaced a predetermined distance from said pair of movable contacts when said access lid is closed to condition the shoulder of said impact portion for impacting on said pair of movable contacts when said access lid is opened, said spring supporting said pair of movable contacts against said shoulder when said access lid is open, said spring maintaining the bridging relation of said pair of movable contacts with said stationary contacts after the axial movement of said support means in said one direction when said access lid is closed and inducing the axial movement of said support means in the opposite direction to cause said shoulder to impact on said pair of movable contacts when the access lid is opened, the mass of said support means in cooperation with said predetermined Distance and the rate of said spring being sufficient to suddenly and surely break the bridging relation and any tack welding of said movable contacts with said stationary contacts, thereby to open the power supply circuit as soon as said access lid is opened.
 2. The combination of claim 1 wherein said clothes washer wall is horizontal and the axial movement of said support means in said opposite direction is aided by gravity.
 3. A magnetically operated switch adapted to be located adjacent a magnet means which is selectively present or absent from the location of the switch, said switch comprising a switch housing of nonmagnetic material generally imperforate to moisture and access from one side thereof, a pair of stationary contacts in said housing adapted to be electrically connected in an electrical power supply circuit, a pair of movable contacts in said housing for electrically bridging said stationary contacts to close said power supply circuit, and support means for said pair of movable contacts axially movable in said housing in two directions, said support means including as a unit an actuating plate portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said pair of movable contacts between said spring and said impact portion, said actuating plate portion being of magnetic material axially movable in response to the presence of said magnet means for axially moving said support means in one direction to move said movable contacts into bridging relation with said stationary contacts, said support means axially movable in the opposite direction in response to the absence of said magnet means to move said movable contacts out of bridging relation with said stationary contacts, said shaft portion loosely interfitting with said pair of movable contacts and axially movable relative thereto, said impact portion having a shoulder spaced a predetermined distance from said pair of movable contacts when said magnet means is present, said spring supporting said pair of movable contacts against said shoulder when said magnet means is absent, said spring maintaining the bridging relation of said pair of movable contacts with said stationary contacts after the axial movement of said support means in said one direction when said magnet means is present and inducing the axial movement of said support means in the opposite direction to cause said shoulder to impact on said pair of movable contacts at the moment said magnet means is absent, the mass of said support means in cooperation with said predetermined distance and the rate of said spring being sufficient to suddenly and surely break the bridging relation and any tack welding of said movable contacts with said stationary contacts, thereby to open the power supply circuit as soon as said magnet means is absent.
 4. The magnetically operated switch of claim 3 wherein said magnet means is a permanent magnet.
 5. A magnetically operated switch adapted to be located adjacent a magnet means which is selectively present or absent from the location of the switch, said switch comprising stationary contact means adapted to be electrically connected in an electrical power supply circuit, movable contact means for electrically connecting said stationary contact means to close said power supply circuit, and support means for said movable contact means movable in two directions, said support means including as a unit an actuating portion, impact portion, shaft portion and spring, said spring having one end supported on said shaft portion and another end yieldingly supporting said movable contact means between said spring and said impact portion, said actuating portion being of magnetic material movable in response to the presence of said magnet means for moving said support means in one direction to move said movable contact means into connecting relation with said stationary contact means, said support means movable in the opposite directiOn in response to the absence of said magnet means to move said movable contact means out of connecting relation with said stationary contact means, said shaft portion freely movable relative to said movable contact means, said impact portion having a shoulder spaced a predetermined distance from said movable contact means when said magnet means is present and said movable contact means is in connecting relation with said stationary contact means, said spring supporting said movable contact means against said shoulder when said magnet means is absent, said spring maintaining the connecting relation of said movable contact means with said stationary contact means after the movement of said support means in said one direction when said magnet means is present and inducing the movement of said support means in the opposite direction to cause said shoulder to impact on said movable contact means at the moment said magnet means is absent, the mass of said support means in cooperation with said predetermined distance and the rate of said spring being sufficient to suddenly and surely break the connecting relation and any tack welding of said movable contact means with said stationary contact means, thereby to open the power supply circuit as soon as said magnet means is absent. 